Recently, various devices capable of performing user input through motions of the user via an NUI device have been developed.
In particular, user interfaces configured to, in a game or smart device, recognize motions of a user and perform specific functions based on the recognized motions have been developed.
In this case, to recognize motions of a user, a motion of a user may be successively captured 30 or more times per second generally via a camera, a motion sensor or the like attached to an NUI device, the location of each joint based on the skeleton of the user may be extracted from the captured image frames, and the rotation angle of the joint estimated based on the extracted location of the joint may be calculated.
In this case, since the estimated rotation angle is estimated based on the location of each joint only for a single image frame, the continuity between the rotation angles of the same joint included in successively captured image frames is not taken into consideration.
Accordingly, a problem arises in that an instable rotation angle occurs among the estimated rotation angles of each joint. To overcome this problem, an instable rotation angle is removed by applying a Gaussian filter.
However, although this method can reduce instable rotation angles, the 3D location of each joint becomes different from the location of the joint, calculated from captured image frames, due to a variation in a rotation angle, and thus problems arise in that motion information regarding a fast speed motion is lost and a foot sliding effect in which a motion of a user restored based on the lost motion information becomes insensitive and loses accuracy occurs.
Accordingly, there is a need for a technology for overcoming the above-described problems.
In connection with this, Korean Patent Application Publication No. 10-2010-0025048 relates to an image analysis method and device for capturing a motion, and is configured to detect a plurality of human body regions by tracking skin colors to track motions of a human body by using images received from at least one image input device and to correct the coordinates of the detected human body regions by using image correction parameters, thereby tracking the motions of the human body regions. However, the technology disclosed in the above Korean patent application publication does not overcome the above-described problems.
Meanwhile, the above-described background technology corresponds to technical information that has been possessed by the present inventor in order to contrive the present invention or that has been acquired in the process of contriving the present invention, and cannot be necessarily viewed as a well-known technology that had been known to the public before the filing of the present invention.